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圓錐體的體積為1/3 x 廿 x R2 x H = V (廿=3.14)

1/ 圓錐的體積是1186.92立方米,高是14米,底面半徑是多少米?
若圓錐體體積為1186.92, 高為14m, 固

1/3 x 廿 x R2 x 14 = 1186.92
1/3 x 廿 x R2 = 1186.92/14
1/3 x 廿 x R2 = 84.78
1/3 x R2 = 84.78/ 廿
1/3 x R2 = 84.78/ 3.14
1/3 x R2 = 27
R2 = 27 x 3
R2 = 81
R = 81 (開方)
R = 9

半徑即9米

2/ 圓錐的體積是376.8立方米,底面半徑是6米,高是多少M?
1/3 x 廿 x 6^2 x H = 376.8
1/3 x 廿 x 36 x H = 376.8
1/3 x 廿 x H = 376.8/36
1/3 x 廿 x H = 10.47
1/3 x H = 10.47/ 廿
1/3 x H = 10.47/ 3.14
1/3 x H = 3.33
H = 3.33 x 3
H = 10

高即10米

3/ 圓錐的體積是329.7立方厘米,高是12.6CM,底面半徑是多少CM?
1/3 x 廿 x R2 x 12.6 = 329.7
1/3 x 廿 x R2 = 329.7/ 12.6
1/3 x 廿 x R2 = 26.17
1/3 x R2 = 26.17/ 廿
1/3 x R2 = 26.17/ 3.14
1/3 x R2 = 8.33
R2 = 8.33 x 3
R2 = 25
R = 25 (開方)
R = 5

半徑即5CM

4/ 圓錐形的糖果體犢是1.57立方厘米,高是1.5CM,它的底面積是多少平方厘米?

用圓錐體體積的方程式, 計出底的半徑:
1/3 x 廿 x R2 x 1.5 = 1.57
1/3 x 廿 x R2 = 1.57/ 1.5
1/3 x 廿 x R2 = 1.05
1/3 x R2 = 1.05/ 廿
1/3 x R2 = 1.05/ 3.14
1/3 x R2 = 0.33
R2 = 0.33 x 3
R2 = 1
R = 1(開方)
R = 1

即底的半徑為1CM

圓的面積為廿R2
= 廿 x (1)^2
= 3.14 x 1
= 3.14

即底的面積為3.14平方厘米

自己禁.我冇計數機
圓錐的體積=(3.14*半徑的2次方)*高*1/3
全部用體積*3再÷高再÷3.14再開平方根(求底面積的省略:÷3.14開平方根)

錐體體積公式: 1/3 *r^2 *π*h
a)1186.92= 1/3 *r^2 * π*14
r=9m

b) 376.8=1/3*6^2 *π*h
h=10m

c) 329.7=1/3*r^2*π*12.6
r=5cm

d) 1.57= 1/3*r^2*π*1.5
r=1
面積=π*r^2
=3.14*1^2
=3.14cm^2